Apparatus for molding articles



July 2, 1968 E. vALYl 3,390,431

APPARATUS FOR HOLDING ARTICLES Original Filed Sept. l0. 1963 2Sheets-Sheet 1 IN VEN TOR. Enuy fvuyz mw .NwTm

/Illllll/llI/lh 'llllllllllllll July 2, 1968 E. l. VAL 3,390,431

APPARATUS FOR MOLDING ARTICLES 2 Sheets-Sheet 2 Original Filed Sept. 10,1963 INVENTOR. EZMEey r VBL/l ATTDRNEY United States Patent O 3,390,431APPARATUS FOR MLDING ARTICLES Emery i. Valyi, Riverdale, N.Y. 10471@riginal application Sept. 10, 1963, Ser. No. 308,020, now Patent No.3,330,894, dated July 11, 1967. Divided and this application Apr. 14,1967, Ser. No. 630,971

3 Claims. (Cl. 18-5) ABSTRACT F THE DISCLOSURE A b'low molding apparatuswherein a blown article is formed from a parison carried on a blow coreincluding a blow mold into which the blow core is inserted with theparison thereon for blowing into the shape of the finished article. Theblow mold carries a seal for the blow core through which the blow corecan be withdrawn from the blown article in the blow mold withoutbreaking the seal. After the blow core has been so withdrawn, fluidpressure is introduced through the seal for maintaining the blownarticle under pressure while still in the blow mold.

This application is a division of my co-pending application Ser. No.308,020 filed Sept. 10, 1963 and now Patent No. 3,330,894.

This invention relates to apparatus for molding articles of organicplastic material and more particularly to a method and apparatus formolding wherein a parison is first formed in a parison die and is thenblown into the final form in a blow mold.

Apparatus of this general type is shown in my U.S. Patent No. 3,029,468dated Apr. 17, 1962. This patent shows a separable blow mold shaped toform the final article and through which a blow core forming the innerwalls of a parison die extends. An injection nozzle aligned with outermembers of the parison die is disposed in the injection zone outside ofthe blow ymold cavity. The arrangement is such that the parison isformed with the blow core extending entirely through the open blow moldand into the injection zone. The blow core with the parison thereon isthen retracted from the injection zone into the blow mold cavity afterwhich the blow mold is closed and the parison expanded by fluid pressureinto its final form.

Other apparatus designed to produce blown hollow articles from parisonsthat were molded around a blow core are well known in the art as forexample U.S. Patent No. 2,872,700.

In molding operations of the above type it is necessary to control thetemperature of the blow core which becomes heated by contact with thehot plastic material. This has necessitated forming the blow core, overa substantial portion of its length with channels for the circulation ofthe cooling fluid. The blow core must also be equipped with a conduitfor blow air. In a long, slender blow core it is difficult to maintainsufficient -mechanical rigidity while at the same time providingadequate fluid passages for the above purposes. Also, due to the lack ofaccessibility, diiculty is encountered in applying a parting agent tothe surface of the blow core to preventthe parison from adheringthereto.

An object is to provide a cycle of operation wherein the blow core isremoved from the blown article substantially immediately after blowingand wherein the hollow article is maintained under pressure in the blow`mold after the removal of the blow core.

Various other objects and advantages will be apparent as the nature ofthe invention is more fully disclosed.

The invention will be better understood from the following descriptiontaken in connection with the accompanying drawings in which a specificembodiment has been set for the purposes of illustration.

3,390,431 Patented July 2, 1968 ICC In the drawings:

FIG. 1 is a longitudinal section with parts in elevation showing a moldand die embodying the invention;

FIG. 2 is a similar section showing the blow mold in closed positionwith the parison in place before blowing;

FIG. 3 is a similar section showing the blow core fully retracted intothe cooling chamber; and

FIGS. 4 and 5 are transverse sections taken on the lines 4 -4 and 5-5respectively of FIG. 2.

Referring to the drawings more in detail the invention is shown asincluding a cover die 24 having a bottom wall 25 and a cylindrical wall26 forming the outer wall of the parison die. Cover die 24 may of coursebe parted axially or radially and may be formed of several components-movable in relation to each other to facilitate removal of the parisonto be described. The cover die 24 is mounted on a fixed support 27. Aninjection nozzle 29 is aligned with and pressed against orifice 31 inthe wall 25.

A blow core 35 having an end wall 36 and a cylindrical wall 37 isadapted to form the inner surface of the parison. The blow core has anenlarged cylindrical portion 38 adapted to form the neck of the parisonand is carried by an end wall 39 of a cylindrical member 40.

The cylindrical member 40 is carried by a forward end wall 41 attachedto a slide plate 42. An air conduit 43 extends through the walls 39 and41 to supply air to blow-air passage 44 of the core 35. A diametricalwall 45 divides the cylinder 40 into chambers 46 and 47. Cooling fluidis supplied to the chambers 46 and 47 by radial inlet and outletpassages 48 and 49 in the wall 41. Wall 39 is provided with passages 50and 51 for the purpose to be described.

A sleeve attached to a slide plate 56 is disposed around the cylindricalmember 40 and is formed with an end wall 58 having an enlarged hubportion 59 carrying an expanding seal 60 which makes a fluid tight sealwith the blow core 35. The hub 59 and seal ring 60 seat within a recess61 in the cylindrical wall 26 of the cover die 24 to form an end closurefor the parison die. The seal ring 60 may be of th expanding diaphragmtype adapted to maintain a liquid tight seal with the blow core as thelatter is reciprocated during the molding operation.

rl`he blow mold comprises a pair of halves 62 and 63 which are adaptedto be separated or closed by suitable means, not shown. Parts 62 and 63have recesses 64 and 65 which together form the cavity for the bottle orthe like to be blown therein and have semi-cylindrical surfaces 66 and67 which are adapted to clamp the neck 68 of the parison when the blowmold parts are closed. The surfaces 66 and 67 are shown as formed withthread forming recesses 73 and 74 which are adapted to form raisedthreads 75 on the neck 68 of the formed bottle 77. The parts 62 and 63have registering bottom forming me-mbers 70 and 71 which are adapted toclose the bottom of the blow mold cavity.

In operation with the blow mold parts 62 and 63 in separated position asshown in FIG. 1 the blow core 35 is positioned within the wall 26 of thecover die 24 and with its inner end 36 spaced from the end wall 25 toform the cylindrical side wall and dished bottom wall 81 of the parison.The hub 59 and sealing ring 60 are `disposed within the recess 61 in thecover die 24 to form a closure for the parison die. With the parts inthis position the parison is injected through the nozzle 29 and orice31.

After the parison has been thus formed the blow core 35 with the parisonthereon and the sleeve 55 are retracted axially as a unit to withdrawthe parison from the cover die 24 into alignment with the blow moldparts 62 and 63 and the blow mold is closed about the parison as shownin FIG. 2. Air is then admitted through the passage 44 of the blow core35 for expanding the parison into the recesses 64 and 65 of the blowmold to form the bottle 77. The surfaces 66 and 67 of the blow moldclamp the neck 68 of the parison and shape the corresponding bottleneck, as shown in FIG. 3.

After the bottle has been blown the blow core is retracted axially fromthe bottle and blow mold into the sleeve S5 with its surface in contactwith the liquid which is circulated through the chambers 46 and 47 andthrough passages 50 and S1 to the space formed between the blow core andthe sleeve 55.

The seal ring 60 maintains a tight seal with the surface of the blowcore to prevent escape of the coolant. The coolant may contain orcomprise a parting agent to apply a film of parting material to the blowcore for facilitating the blowing of the parison. The blow mold halvesare then opened, the bottle removed and the cycle repeated.

As an alternate to retracting blow core 35 only par tially into sleeve55, as shown in FIG. 3, the blow core may be fully withdrawn into thesleeve and the opening closed by the expanding seal 60 alone, or by aseparate closure member, not shown. Pressure should be maintained withinthe blown bottle after blow core 35 is retracted therefrom and while thebottle is cooling in the blow mold and provision is made for theintroduction of air for this purpose other than through the blow core,such as through passage 58a in the end plate 58, as indicated by dottedlines in FIG. 3.

The uid contained in sleeve 55 may be a vapor or mist-like dispersion ofa parting agent or a gas. For example, water or oil may be used and alsosteam or air, and the parting agent may be chosen from a variety ofcommercial compositions of the silicone family, or the like.

It will be noted that the fluid serves to control the temperature of theblow core between parison injections and eliminates the necessity forcooling ducts or passages within the blow core itself.

What is claimed is:

1. Apparatus for forming hollow articles of organic plastic materialcomprising a parison die including a blow core having side and end Wallsadapted to form the inner surfaces of the corresponding walls of theparison and having a uid passage for the supply of fluid for expandingthe parison into a blow mold, an outer die member having a bottom walland side walls adapted to form the outer surfaces of the correspondingparison walls and registering with said blow core to form a closedparison die, and a blow mold, means retracting said blow core with theformed parison thereon from said parison die and introducing the sameinto said blow mold, means blowing said parison in said blow mold toform said hollow object, means retracting said blow core from saidhollow object in said blow mold and means maintaining said hollow objectunder fluid pressure while in said blow mold after the retraction ofsaid blow core.

2. Apparatus for forming hollow articles of organic plastic materialcomprising a parison die including a blow core, a blow mold, meansretracting said blow core with the formed parison thereon from saidparison die and introducing the same into said blow mold, means blowingsaid parison in said blow mold to form said hollow article, meansretracting said blow core from said hollow article in said blow mold andmeans maintaining said hollow article under fluid pressure while in saidblow mold after the retraction of said blow core.

3. Apparatus for making a parison of organic plastic material comprisingan outer die member having a cylindrical wall and an end wall adapted toform the outer surfaces of the parison wall and a blow core having anend wall and a cylindrical wall shaped to form the inner surface of theparison wall and adapted to form, with the outer die member, a closedparison die, injection means for injecting the plastic material throughthe end wall of said outer die member, a retractable sleeve having anend wall, said end wall having an opening through which said blow coreextends and carrying an expanding seal engaging the surface of said blowcore to form a fluid tight seal therewith, said seal engaging the endsurface of said outer die member to form an end closure for the parisondie, means retracting the sleeve and blow core axially from said outerdie member with the parison in place on said blow core for exposing theparison for blowing, a blow mold having a cavity into which the parisonis blown to form a hollow object, means introducing the blow core withthe parison thereon into said blow mold with said seal engaging saidblow mold to seal the blow mold cavity, means blowing the parison intoconformity with said cavity, means retracting said blow core entirelyout of the blown object while maintaining said seal and means supplyinguid pressure through said seal for maintaining said hollow object underpressure while in said blow mold after the retraction of said blow coretherefrom.

References Cited UNITED STATES PATENTS 2,262,612 1l/1941 Kopitke 18-5 X3,002,225 itl/1961 Goller 18-5 3,244,778 4/1966 Ninneman 264-97 XFOREIGN PATENTS 1,106,868 12/1955 France.

WILBUR L. MCBAY, Primary Examiner.

